Here's how it's formed:

* Ammonium ion (NH₄⁺): Ammonium is a polyatomic cation formed by the combination of ammonia (NH₃) and a hydrogen ion (H⁺).

* Chloride ion (Cl⁻): Chloride is a monatomic anion formed when a chlorine atom gains an electron.

To form a neutral compound, one ammonium ion (NH₄⁺) combines with one chloride ion (Cl⁻), resulting in the formula NH₄Cl.